1. Field of the Invention
This invention relates generally to perpendicular magnetic recording systems, and more particularly to a system with fast switching of the magnetization direction of the perpendicular write head.
2. Description of the Related Art
Perpendicular magnetic recording, wherein the recorded bits are stored in a perpendicular or out-of-plane orientation in the recording layer, allows for ultra-high recording densities in magnetic recording hard disk drives. The write head must be able to write data not only at high bit-density but also at high data-rates. The write speed is particularly important in enterprise disk drives. However, the switching time for the main pole of the write head to switch from one magnetization direction to the other is a limiting factor as the data rate is increased. At high data-rates, the available magnetic flux from the write head, as seen by the recording layer on the disk, is dominated by the low-frequency flux output of the write head. The reason for such loss of write flux includes a slow intrinsic time-constant of the magnetization reversal in the main pole of the write head. Also, lower data-rate systems still require additional overshoot of the write current from the disk drive's write driver circuitry to aid in the magnetization reversal. Also, this additional overshoot requires additional power from the write driver circuitry.
Thus for both high data-rate and lower data-rate perpendicular magnetic recording, what is needed is a write head and system that reduces the magnetization reversal time and overshoot for the main pole of the write head.